Fuel System

[woodseaves]

Hi all,

Has anyone got a diagram of the fuel pipe system? I am aware of the one that Agriline use to advertise and sell their made up pipes but I don't trust it. I am trying to get the system back to what it was when it was born. Someone in the past has had a real go at altering it. Maybe just a couple of pipes but enough to frighten me.

here's hoping

[brownsmule]

Hello; Look on the post about "ferrule" and there is the information that you desire. Good Luck on your Dexta and putting it back to original condition. brownsmule

[woodseaves]

That's the one from Agriline!!!

[Bensdexta]

The Agriline diag is OK. It's a straight lift from the Dexta Parts List, copy downloadable from fordson-dexta.de.
I recommend the parts list , it's pretty useful

[dexta4]

dont get one from agriline i could have made a better one myself than the one that turned up it wasn't how it was pictured and to top it off it leaked and wont stop leaking i'll have to do what i should have done in the first place and make one

[woodseaves]

OK Ben

so what you are saying is use the Agriline pipe plan? Are all the descriptive parts for each pipe accurate? I was speaking to them just this week and one of the chaps said "what is that pipe doing there". This is what makes me untrusting. I haven't got the time at the moment but later I will describe what happened after I repiped some of it, it was scary I can tell you. More later.

Regards

[Bensdexta]

OK Ben

so what you are saying is use the Agriline pipe plan? Are all the descriptive parts for each pipe accurate? I was speaking to them just this week and one of the chaps said "what is that pipe doing there". This is what makes me untrusting. I haven't got the time at the moment but later I will describe what happened after I repiped some of it, it was scary I can tell you. More later.

I recommend you download the official Fordson parts list from Stefan's site. That way you will see all the parts with their correct descriptions and part nos, rather than just what Agriline sells. Also of course check the workshop manual on Stefan's site to make sure you work & operate correctly.

[woodseaves]

Thanks Ben,

Just one more related question, what would happen if I started my Dexta without a heater plug in situ?

I need to know if this was the cause of my upset this afternoon.

Regards

[Bensdexta]

Just one more related question, what would happen if I started my Dexta without a heater plug in situ?

Did you remove the heater plug and leave the hole open? If so that is not a good idea.

Without going to look at my tractor, I believe the heater is on the cylinder head side, ie downstream, of the throttle butterfly valve. So with a hole in the manifold there I think you will effectively have a wide open throttle setting and worse still closing the throttle with the control lever will have no effect, as the pneumatic fuel pump governer is no longer measuring the correct suction in the inlet manifold. Only way to stop her then is by pulling the stop lever. Is that what happened?

Hopefully no harm done.

[woodseaves]

Yes

That is exactly what happened, I had fitted the new manifold and forgot to insert the heater plug so yes there was a hole. She started straight away but just accelerated. As you said the throttle had no control and the stop cable did not stop the engine either. Panic took over, there was smoke everywhere, I did not know what to do. I shot off down the road to see if my neighbour could help but he was out. All of a sudden the noise stopped and for some reason the engine stopped. What kind of damage could I have done and how can I check?

I was terrified. But still here to tell the tale

Regards

[Bensdexta]

Sorry to hear that. It's easy to screw up and these machines can bite, but fortunately you are unharmed which is the main thing. When I take things apart I try to take lots of photos and keep all the parts togther in a bag or bin, so hopefully on reassembly each one finds a home. And follow the manual step by step during both disassembly & assembly. Then when I've finished - check the manual again.

I'm surprised that the stop lever didn't cut off the fuel and stop her pretty quick. I guess whether you did any damage or not depends on whether the engine oversped, but if it had significantly over sped something would probably have broken. I think I would try turning the engine over by hand very slowly using a spanner on the crankshaft pulley nut. If she turns smoothly that is a good sign. Check the oil & water levels. Then try starting her with heater plug in!! and watch the oil pressure and water temp like a hawk. Watch for leaks.

I would await further advice from more knowledge folk than me.

All the best,

[woodseaves]

Thanks again Ben, I'll wait to see if anybody else contributes.

I suppose in one sense it's a good thing it happened it might alert other beginners to the danger.

Regards

[GERRY]

Hi just been reading your post hopefuly no damage has been done , before you start up again make sure to find out why the stop did not work , another thing about the dexta is that they can be put in gear easily and if you are not sitting on the tractor when starting, it can move foward, just be aware of little things which can avoid accidents, Regards Gerry

[Brian]

Sorry to be pessimistic but you may have done major damage to the engine.

It is possible that she could run on oil passing the pistons if you were using a light W oil.

We used to get the same sort of problem when a Major or 590E leaked diesel into the sump from a fractured leak off pipe.

Plug your manifold and try to start her again. If she runs OK you will have got away lightly.

If not, you have learnt an expensive lesson.

This problem would only occur on a tractor with a vacuum governed pump.

[woodseaves]

Thanks for all the comments.

Before I attempt to restart it I must point out one other thing about the fuel piping.

After a very detailed inspection of the fuel pipes it is clear that the only pipe that is not as per the diagram (in the parts manual) is the pipe from the connection under the fuel tank to the inlet manifold. Instead of this pipe someone, not me, has introduced a new pipe from the top of the fuel filter and connected it to the inlet manifold.

Now the dexta ran OK setup like this with the old manifold (if you remember this was the one that had an additional hole drilled in the top to take a heater plug AND a fuel pipe both into the same hole)so as the cold start was activated the injected fuel went straight onto the heater plug.

I have replaced the manifold with an original setup but have kept the fuel line from the filter to the manifold.

This set up was probably introduced because the outlet under the tank only had provision for one pipe.

The fuel filter now has three fuel pipes attached to it, the two at the bottom and the new one coming out of the top.

My fear is that in the old manifold there may have been some sort of non return valve in the heater plug that only allowed fuel through when the pump was primed (because one of the fuel lines attached to the bottom of the fuel filter comes from the fuel pump).

my question is this, under my setup now, does fuel only get to the inlet manifold when it is physically pumped to it from the fuel pump?

so there you have it, it stays OFF until I am 100% sure that what happened yesterday won't happen again today.

Assure me!!!!

Regards

Looking at the fuel filter that is on it and the one in the parts list they are completely different

[commander]

The original setup had a small check valve in the line where it joined the manifold. It was designed to open under slight pressure from mashing the primer bulb with your thumb. Many people also add a small manual cutoff valve in the line.

I suspect that the lift pump will build up enough pressure to keep that valve open and inject additional fuel into the
manifold all the time it's running....not a good scenario.

Would be best to convert it back to an original primer bulb setup, or perhaps a solenoid controlled valve so that this extra fuel flows only when needed - at a 'cold start'.

You could unhook this line and temporarily plug up the hole in the manifold and at the fuel filter. These old girls usually start up fine in warm weather without the cold start.

There have been several previous posts on some variations on the stock cold start. A search should reveal some more info.

And don't forget to check out the stop cable and linkage as mentioned above.

[Brian]

If you have a pipe from the return to tank line on the filter, that goes straight to the manifold without a check valve in it, you are in deep trouble.

Fuel can go, unrestricted, into the inlet manifold and you can get everything from run away engines to hydraulic lockup.

The later type heater/ spray type plug systems had such a valve built in, the Dexta system did not. Theory being that fuel would be controlled by the valve in the pump built in to the fuel tap. This worked initially but even back in the 1960's the tractors gave problems drawing fuel past the valve in the tap into the manifold. To correct this problem, a small on/off tap was fitted in the fuel line close to the manifold.

The tap was turned on for using the cold start heater and once the engine was running it was turned off, this isolated the fuel tap primer.

I would strongly advise you fit such a tap in the line from your filter to the manifold, otherwise you will have fuel under pressure always being pumped in there.

[woodseaves]

The stop cable was working fine before this incident so I have no idea why it didn't work. It's job is to stop the fuel I believe but if there was still fuel getting into the manifold then would this be a reason for it not to work?

I have done away with the pipe from the filter to the manifold and blocked both holes.

I attempted to start her, she turned over but I detected water from somewhere on the engine block I think.

I think it is going to cost me, if it is recoverable.

I'm gutted.